Inspection of the Wheel and Tire
Walk around the vehicle and visually inspect each wheel and tire assembly.
- Inspect tire condition for the following:
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valve stem caps on every tire, screwed on finger-tight
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bulges, cracks, cuts, and penetrations
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oil contamination (petroleum derivatives will soften the rubber and destroy the tire)
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tread depth—if tread is less than 4/32 inch (3 mm) on any front tire, or less than 2/32 inch (1.5 mm) on any rear tire, replace the tire
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debris lodged between dual tire sets
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- Check tire inflation.For inflation pressures and maximum loads, see the tire manufacturer's guidelines. Inflate the tires to the applicable pressures if needed.If a tire has been run flat or under-inflated, check the wheel and tire for damage before adding air.Keep compressed air reservoirs and lines dry during tire inflation. Use well-maintained inline moisture traps and service them regularly.
- Examine each rim and wheel component.
- Remove all dirt and debris from the assembly. Rust streaks
or metal build-up around stud holes, or out-of-round or worn stud
holes, may be caused by loose wheel nuts.
Warning: Have any worn or damaged wheel components replaced by a qualified person using the wheel manufacturer's instructions and the wheel industry's standard safety precautions and equipment. Otherwise a vehicle or workshop accident could occur, possibly resulting in serious personal injury or death.
- Inspect for broken, cracked, badly worn, bent, rusty,
or sprung rings and rims.
Notice: Use the recommended torque values and follow the proper tightening sequence. Insufficient wheel nut torque can cause wheel shimmy, resulting in wheel damage, stud breakage, and extreme tire tread wear. Excessive wheel nut torque can break studs, damage threads, and crack discs in the stud hole area.
- Make sure all wheel nuts are tightened. If tightening
is necessary, use the tightening pattern in Fig. or see Fig. to initially
tighten the flange nuts to 50 to 100 lbf·ft (68 to 136 N·m). Then
tighten the flange nuts to 450 to 500 lbf·ft (610 to 678 N·m).
Fig. 1, Tightening Pattern, 10-Stud Disc Wheel
Fig. 2, Tightening Pattern, 8-Stud Disc Wheel
- Remove all dirt and debris from the assembly. Rust streaks
or metal build-up around stud holes, or out-of-round or worn stud
holes, may be caused by loose wheel nuts.
- Inspect the outboard side of all wheel hubs and the hub
oil seal area on the inboard side of each wheel for signs of oil leakage.
If any oil is found on wheel and tire or brake components, remove
the vehicle from service until the leak has been fixed.If needed, fill the hubs to the level indicated on the hub cap. See Group 35 of the Century Class Trucks Maintenance Manual for recommended lubricants.
- Check that mud flaps are undamaged and hang 10 inches (25 cm) or less from the ground.
Warning: Do not operate the vehicle with underinflated or overinflated tires. Incorrect inflation can stress the tires and make the tires and rims more susceptible to damage, possibly leading to rim or tire failure and loss of vehicle control, resulting in serious personal injury or death.
Important: The load and cold inflation pressure must not exceed the rim or wheel manufacturer's recommendations, even though the tire may be approved for a higher load inflation. Consult the rim or wheel manufacturer for the correct tire inflation pressure for the vehicle load.
Notice: A weekly pressure loss of 4 psi (28 kPa) or more in a tire may indicate damage. The tire should be inspected and, if necessary, repaired or replaced by a qualified tire service facility.